Gas compressor and clearance varying means therefor



H. C. GUILD GAS COMPRESSOR AND CLEARANCE VARYING MEANS THEREFOR FiledDec. 16, .1936

INVENTOR HEAD Patented May 31, 1938 Parent oFFleE GAS COIHPRESSOR ANDCLEARANCE VARY- ING S THEREFOR Herbert 0. Guild, New York, N. Y.

Application December 16, 1936, Serial No. 116,143

8 Claims.

My present invention relates to devices for varying the volume of theclearance space in a gas compressor, particularly for the purpose ofvarying the capacity of the compressor, that is, varying the amount(weight) of the compressed gas that a given compressor will deliver,other capacity varying factors remaining the same.

As applied to the case of a compressor of the ordinary cylinder andpiston type, it may be explained that, other things being equal, themaximum compression actually attained, depends upon the point in therearward movements of the piston at which the inlet valve opens, and

upon the point in its forward movement at which the outlet valve opens.

Usually, both the inlet and outlet valves are check valves whichautomatically open and close according as the reciprocating pistonraises or lowers the internal pressure above or below the externalpressures on the valves. Consequently, the normal clearance is usuallymade as small as is mechanically practical.

My invention assumes a normal condition, including predetermined pistonspeeds; and any of the permissible external inlet and outlet pressures,and any displacement-clearance ratio that will give internal pressuressufficiently in excess of the external pressures on the outlet. For anysuch normal condition, increasing clearance space increases the volumeof gas that remainscome pressed in the cylinder when the outletvalvecloses. This increases the distance the piston must travel rearwardduring the suction stroke before said gas can re-expand to pressure lowenough to cause opening of the inlet valve. This decreases the amount(weight) of new gas which can be taken in. In short, other things beingequal, increasing clearance space increases the amount of idlycompressed and re-expanded gas in the cylinder, thereby decreasing theintake and output capacity of the compressor.

While there are other more complicated ways of varying the amount of theidly re-expanding gas, the only simple way, so far as I am aware, hasbeen by adding a definite fixed volume of clearance space, in the formof one or more separate blind pockets, known as clearance controlpockets. As such a pocket must communicate with the clearance space, acommon way of adding it to a compressor supplied through two or moreintake check valves, is to substitute the pocket for one of said valves.

' One object of my invention is to avoid'necessity for suchsubstitutions; and to operatively combine a gas-tight clearance pocketwith at least one of the inlet valve elements, so that a valve passagenormally used for the unidirectional supply of gas to the cylinder, maybe cut off from the supply and utilized for the idle to and fro flowinto and out of said pocket. I accomplish this by simple mechanismwhereby the valve may be held open and a gas-tight chamber formed inoperative relation for in and out flow of the addi-- tional compressingand expanding gas, through the thus opened valve passage.

While this broad principle may be applied to any compressor having twoor more inlet valve elements, the necessary mechanism is simpler,cheaper and more efficient when applied to check valves, particularlyannular plate valves such as are commonly employed in this art. In suchcase simple well known mechanism, including fingers extending throughthe passage or passages for inlet of gas to the valve plates, may beemployed for holding the valve plates open; and the valve openingmechanism may be operated interdependently with pocket closing elements.

In so much as the inlet valve cannot be functioning as such, when theblind pocket is functioning, it will be obvious that the invention isparticularly useful where two or more separate valves or valve elementsare employed. In fact, one of its most practically useful applicationsis in connection with compressors wherein as many valves are employed ascan be arranged around the clearance space of the cylinder. Commonly,three, four or more intake valves or valve elements are employed for theintake, and a similar number for the outlet.

The above and other features of my invention may be more readilyunderstood from the following description in connection with theaccompanying drawing, in which Fig. 1 is a more or less conventional ordiagrammatic View showing a compressor in transverse section, takenapproximately in the plane of the clearance space, and showing manifoldpassages with a multiplicity of intake and outlet valves;

Figs. 2 and 3 are detail sections on line 2-2, Fig. 1, showing an intakevalve provided with valve-opening and pocket-forming elements, inaccordance with my present invention; Fig. 2 showing the position of theparts when the intake valves are functioning, and Fig. 3 the positionwhen the valve plates are held inoperative and a blind pocket space hasbeen closed in above them.

Figs. 4 and 5 show modifications.

In Fig. 1, the clearance space is surrounded by cylinder wall A, inwhich are openings controlled by four ordinary annular plate inlet valveassemblies B, B, two of which are shown as equipped with my pocketforming elements C, C. The outlet valve assemblies D, D, are like B, B,except that the valves open outwardly instead of in- Wardly.

The cylinder A carries an outer casing E closing in an annular spaceseparated into an intake manifold F and an outlet manifold G, by thepartitions H, H.

As shown, the valve assemblies are insertable through manholes in theouter casing E, which are closed by gas-tight cover plates J throughwhich extend screw thrust members K, K, whereby the valve assemblies areclamped gas-tight in the openings of cylinder A.

In Fig. 2, the valve assembly B is conventionally indicated as includingthe usual upper disc I, adapted to be clamped gas-tight in the openingthrough the wall of cylinder A; and a lower disc 2 secured to the upperdisc by a screw. Intake of gas is through passages 3, 3, in the uperdisc, and passages 3a, 3a, in the lower disc. The lower surface of theupper disc forms seats for the ring plate valves 4, each of which isnormally held against its seat by springs 5. These springs are onlystrong enough to ensure seating of the valve against a slight pressuredifferential. Consequently, as soon as the piston head is retracted farenough to reduce the internal pressure below the gas pressure in thesupply manifold minus the spring pressure, the supply pressure forcesthe valve plates downward and they remain open until the piston movesforward again, and compresses the gas enough to make the internalpressure plus spring pressure exceed the supply pressure; whereupon thecombined upward pressures close the valve.

In the ordinary case, this valve assembly is held down by the thrust ofa screw K, as described in connection with Fig. 1. In the present case,however, the valve assembly is utilized as the bottom of the clearancepocket and is held down by tubular member 6, which afiords side wallsfor said pocket; and is forced into air-tight engagement with the uppersurface of said assembly by screws K, K.

The upper part of tubular member 6 is ventilated for free inlet of gas,while the lower portion affords imperforate side walls of the pocket.The side wall portion of the pocket space is formed with a valve-likeseat 1, adapted to be closed gastight by plate 8, an edge portion ofwhich accurately fits the seat I. This cover plate 8 may be raised orlowered by any suitable means, such as screw K.

The means for holding open the valves when this pocket space is closed,is shown as including fingers III, which are carried by plate 8, andwhich extend through the ordinary gas inlets. These fingers III are ofproper length to hold open the ring valve plates 4, when the fingers aremoved downward the distance required to seat the plate 8 and form theclosed pocket, as shown in Fig. 3.

Figs. 4 and 5 show modifications, the most important of which isutilizing an adjustable piston in place of cover plate 8 and making thefingers in telescoping sections instead of the integral fingers I0.Another optional modification is making the member 6 that forms the sidewalls of the compression space, integral with the top plate I of thevalve assembly.

So far as the parts are the same, the reference numerals are the same,and where they are similar the same numerals with an exponent are usedas far as possible.

In Fig. 4, the plate I a is integral with the cylinder member 60. sothat the compression chamber is an integral cup, and it is closed in andopened by the adjustable piston 8a, which is like cover plate 8, and isvertically adjustable by any suitable means, which may be a swivelledscrew like K, Fig. 2.

The valve opening finger is in two telescoping sections including thefinger proper Illa and the tube II with which it telescopes. The tube isprovided with a slot I2, in which slides the stop pin I3 carried byIlla; and in the upper end of tube II is the spring I4 which is powerfulenough to open the valve whenever Fig. 10a. contacts therewith.

In the position shown in the drawing, the piston 8a. is at the lowerlimit of its movement, and the pin I3 is at the upper end of slot I2.When the piston is withdrawn the spring continues to push the finger andhold the valve 4 open until the piston reaches a suflicient height sothat the pin I3 comes in contact with the bottom of slot I2, whereuponthe valve closes.

In Fig. 5, the construction and operation is similar except the entiretube I I0 with its slot I2 is located entirely above the piston and theslot is closed in gas-tight, by sleeve I5, which is brazed or welded totube H0, at the top and bottom of the slot. This gives a much longerrangeof piston movement and the cylindrical part of the cup may be'muchhigher, giving greater maximum volume for the clearance pocket.

While I have shown and described in detail a simple and novelconstruction for closing a pocket, opening the valve and utilizing theValve passages as means for increasing the volume of the clearancespace, as applied to a common type of compressor and valve, it will beobvious that many variations are possible, as for instance, means forrendering the movable valve elements inoperative, need not be fingers,and need not be carried by or even interdependent with the operation ofthe means for closing in the pocket space. Also the means for closingthe pocket space need not be a cover plate, provided the pocket formingelements comprise at least two relatively movable members that arecapable of adjustment for closing a pocket and cutting off the gassupply in one position; and for leaving a free gas supply inlet, inanother position. Also the principle may be useful Where the movablevalve elements are not plate valves and are not even check valves. Alsothe volume of the pocket may be varied to suit the compressor. Alsowhile I have shown a valve assembly in which there are two separate ringplate valve elements, this is not essential, and where there are twovalve elements as shown, only one of them need be opened and itspassages closed in by a pocket.

As before indicated, it is not necessary or desirable to equip all ofthe intake valves with the pocket forming mechanism because pocketingall of them would cut oif the gas supply completely. In Fig. 1, wherethere are four intake valves, only two of them are shown as equippedwith pockets; but obviously the volume of clearance space may be morewidely varied by having three valves so equipped; and one only may besufficient for certain purposes. The pockets need not all be of the samevolume or of the same mechanical construction.

I claim:

1. A gas compressor having a gas intake manifold formed with severalintake openings communicating with a clearance space in the cylinder,corresponding exterior openings with 010- sures therefor, and checkvalve assemblies insertable and removable through said exterior openingsand each adapted to be fitted gas-tight in one of said openings into theclearance space, each assembly including a plurality of inwardly openingring plate check valves; and, in combination with said parts, means forholding open one or more of said valve plates, and closing in aclearance pocket in reciprocal fiow relation to said valve; said meansincluding a tubular pocket-forming member in said manifold having oneend adapted to fit gas-tight against the intake face of the valveassembly, screw means carried by the external closure and applyingdownward thrust upon said tubular member to force the valve assemblyinto gas-tight fit with its opening into the clearance space; a closuremember for said tubular member and externally operable screw means foradjusting it in gas tight engagement with said tubular member to form agas-tight pocket; and for retracting it; and fingers carried by saidpocket closing member, extending through the gas inlets of said valveassembly and of proper length for engaging and holding open the ringplate valves when said closure is in gas-tight engagement with saidtubular pocket forming member.

2. A gas compressor having a gas intake manifold and at least twoseparate openings therefrom into a clearance space of the compressioncylinder, removable check valve assemblies each adapted to be fittedgas-tight in one of said openings, each assembly having at least oneinlet passage controlled by an inlet check valve element, and at leastone of said valved passages of one of said assemblies being maintainedcontinuously operative for intake supply of gas to said space; and, incombination with said parts, means for holding open the check valveelement of at least one other of said inlet passages to permitalternating fiow of gas to and from the clearance space through the thusopened passage; a hollow member within the intake manifold, adapted toform side walls of a clearance pocket communicating through said openpassage with the interior of the compression cylinder; means forapplying inward thrust to said hollow member to force it against theassembly containing said open passage, and thereby force said assemblyinto gas-tight fit in its opening; and means for completing theclearance pocket, including means for closing said hollow membergas-tight, completely cutting off the open passage from gas in thesupply manifold and ailording a gas-tight space confining saidalternating fiow of gas, thereby aifording additional fixed-volumeclearance space for the compressor.

3. A gas compressor having a cylinder clearance space supplied with gasfrom the source through at least two independent passages eachcontrolled by a separate inlet check valve element; at least one of saidvalve elements being maintained continuously operative for intake supplyof gas to said space; and, in combination with said parts, means forholding open at least one other of said valve elements to permitalternating flow to and from the clearance space through the thus openedpassage; and means for forming a gas-tight chamber, completely cuttingoif supply of gas from the source and atfording an added volumegas-tight space confining said alternating fiow of gas, therebyaffording additional clearance space for the compressor.

l. A gas compressor having at least two intake openings communicatingwith a clearance space in the cylinder, check valve assemblies) eachadapted to be fitted gas-tight in one of said openings, each assemblyincluding at least one inwardly opening check valve; and, in combinationwith said parts, means for holding open a valve of one or more of saidassemblies and closing in a clearance pocket in reciprocal fiow relationthereto; said means including a tubular pocket-forming member having oneend adapted to fit gas-tight against the intake face of the valveassembly, screw means for applying downward thrust upon said tubularmember to force the valve assembly into gas-tight fit with its openinginto the clearance space; a closure memher and externally operable screwmeans for adjusting it in gas-tight engagement with said tubular memberto form a gas-tight pocket; and for retracting it; and fingers carriedby said pocket closing member, extending through the air inlets of saidvalve assembly and of proper length for engaging and-holding open thevalves when said closure is in gas-tight engagement with said tubularpocket forming member.

5. A gas compressor having at least two intake openings communicatingwith a clearance space in the cylinder, check valve assemblies eachadapted to be fitted gas-tight in one of said openings, each assemblyincluding at least one 'in a clearance pocket in reciprocal flowrelation thereto; said means including a tubular pocket forming memberhaving its outlet end integral with the intake face of the valveassembly, screw means for applying downward thrust upon said tubularmember to force the valve assembly into gas-tight fit with its openinginto the clearance space; a closure member and externally operable screwmeans for adjusting it in gas-tight engagement with said tubular memberto form a gastight pocket; and for retracting it; and fingers carried bysaid pocket closing member, extending through the air inlets of saidvalve assembly and of proper length for engaging and holding open thevalves when said closure is in gas-tight engagement with said tubularpocket forming member.

6. The combination specified in claim 5', with the further features thatthe closure member for the pocket is a piston slidable in said tubularmember and the fingers for holding open the valves are endwise slidableand spring pressed to hold the valve open in any of the positions towhich the piston is adjustable.

7. The combination specified in claim 3, with the further feature thatthe means for forming the gas-tight chamber includes a cylinder and apiston adjustable therein; and the means for holding open the valveelements includes valve opening elements operable to hold the valveelements open when the piston is in any of the desired pocket-closingpositions.

8. The combination specified in claim 3, with the further feature thatthe means for forming the gas-tight chamber includes a cylinder and apiston adjustable therein; and the means for holding open the valveelements includes fingers that are endwise slidable and are springpressed to hold the valve elements open when the piston is in any of thedesired pocket-closing positions.

HERBERT C. GUILD.

